Hey, thanks for playing and the feedback!
I'll look into decreasing the particles to keep the frame rate up.
To heal, you select yourself with the mouse and click "Rest and Triage". From there you can apply bandages you've purchased from the vending machine, rip your own clothes up to bandage yourself, use ice to heal bruises or use pliers to pull out shrapnel.
Alternatively you can go to a motel and get a room.